Inheritance of two phenotypes, the virgarcus pattern of partly colored seedcoats and the margo d seedcoat pattern, were studied in common bean (Phaseolus vulgaris L.) materials that segregated jointly for genes controlling the two phenotypes to test the hypothesis of allelism of two genes, D and Z. The F2 progeny from the cross j margo BC3 5-593 × t z virgarcus BC3 5-593 produced an unexpected phenotypic class, margo d, suggesting possible allelism of D and Z. The F2 also produced another unexpected phenotypic class, white seedcoat, for which the genetic hypothesis t j z was made. The F2 from the cross t j marginata BC3 5-593 × t z virgarcus BC3 5-593 provided supporting evidence for the new genotype, t j z, for a white seedcoat. Analysis of the F2 and F3 progenies of 80 random F2 plants from the cross t z virgarcus BC3 5-593 × d j (margo d) BC3 5-593 provided support for the hypothesis that the D and Z loci are allelic. Production of two different phenotypes (white vs. white with two tiny pale gray dots, one each at the raphe and micropyle) for t J/j z in two different genetic and cytoplasmic backgrounds is discussed. The F2 from the crosses d j (margo d) BC2 5-593 × j v margo BC2 5-593 and d j (margo d) BC3 5-593 × j margo BC3 5-593 segregated for d (vs. D) phenotypes, which were found not to be independent of a randomly amplified polymorphic DNA (RAPD) marker (AM10560) associated (1.4 cM) with the Z locus. Because the Z gene symbol has priority, we propose to retain Z for the locus.